Tensioning device



Feb. 18, 1941. H. PARKINSON TENSIONING DEVICE Filed July 10, 1939 INVENTQR:

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Patented Feb. 18, 1941 PATENT OFFICE azzazez 'rnssrosmc nsvrcs l-larold Parkinson, Wllmingto "Joseph Bancroft & 801500.,

in, Del., assignor to Wilmington, DeL,

a corporation of Delaware Application July 10, 1939, Serial No. 283,585

5' Claims.

This invention relates to a machine for riveting tag strings to boards or the like.

In machines of this character (as disclosed, for

example, in my PatentNo. l,423,250,'on which the present invention is an improvement), means are provided for fastening or riveting a short length of string to a board, the string subsequently being used forthe purpose of tying a tag to the board, for instance, a price tag. Boards of this type may be used for various purposes, such as a base on which to wind a length of c loth for sales purposes in retail stores. ,"In this event, the boards are usually of fibrousrcharacten such as cardboard. In general, the operation of a machine of the character mentioned involves feed of strin from a source to a riveting head. at which point the string passes under the head of a rivet which is then secured to the board. Thereafter the board is removed from the machine, drawing a new length of string from the source, and finally the length of string attached to the board is severed from the continuous run extending'b'ack to the source.

The present invention is particularly concerned with a string tensioning device for a machine of this character, i. e., a device for maintaining the string taut and for preventing excessive and undesired unwinding of the string at the source.

One of the primary objects of the invention is the provision of a tensioning device adapted for such use, which device provides more uniform tension than prior arrangements, and which is adjustable as to tension so as to meet diflerent operating conditions, such-as different thicknesses of string.

A further object of the invention resides in the provision of adjustable means whereby the run of string leaving the tensioning device may be disposed at difierent heights above the work table, thereby accommodating diiferent thicknesses of boards to which the string is being riveted.

The invention also'contemplates a tensioning device the operation of which will not be impaired by the passage therethrough of knots or the like.

Other objects and advantages will appear hereinafter as this description proceeds.

In the drawing:

Fig. l is a front elevational view of a string riveting machine equipped with the improved,

tensioning device of the present invention;

Fig. 2 is a side elevational view of the tensioning device on an enlarged scale, taken as indicated by the line 2-2 on Fig. 1; and

.Fig. 3 is a topplan view of the device.

The general structural features of the riveting machine are as follows:

-A work table 4 is'appropriately mounted on a base 6 as by brackets 5. The work table has a 5 lateral guide 1 and a rear guide 8 by means of which the. board indicated at X may be properly positioned.

Above the table is a riveting mechanism ineluding a riveting head 9 through which-rivets 10 II) are; fed into proper position to be driven into the board X. Since riveting mechanism of this character is well known, it is not described in detail herein.

The source of supply of string appears at H in 15 Fig. 1, the string S passing therefrom upwardly through a suitable guide hole l2 in .the work table 4, and thence through various parts of the tensioning device of the present invention generally indicated by the letter T, from which the go string passes laterally under the head of rivet l0 and thence between a pair of cooperating friction gripping elements It and H which, in cooperation with the tensioning device T, serve to maintain a substantially straight run of string 35 through the riveting mechanism as shown in Fig. 1.

.To the left beyond the gripping elements I3, ii, a shear I! is provided by means of which the lengths of string are cut.

In operation, after a rivet III has been driven home, the operator removes the board X, mov-' ing it upwardly and laterally to the left when viewed as in Fig. 1, thereby drawing additional string from the source through the tension device T. This removal of the board X releases the short length of string engaged by the gripping elements l4, and the operator then moves the board downwardly'beyond the left end of the machine so as to bring a succeeding length of the string between the gripping elements 13, II, and also between the open blades of the shear IS. The shear is then actuated, as by a control ba'r I6, so as to sever the string, leaving a short length thereof secured to the board by the rivet. The length of string secured to each board is thus attached thereto intermediate its ends.

The improved tension device includes an angle bracket having a base part ll adapted to be mounted on the table 4 by means of'a bolt It so having a wing nut l9, the base I! being provided with an elongated slot 20 for bolt 18, to permit adjustment of the position of the tensioning device with respect to other parts. The bracket also includes an upstanding plate part 2| which serves to carry the tension elements themselves and also a guide member described hereinafter.

A pair of cooperating dished friction gripping elements 22, 22 are mounted on a bolt 23 which is secured to the plate 2| by nuts 24. The friction elements 22 are spring-pressed toward each other by the compression spring 25, adjustable by means of knurled nut 26. The bolt 23 and thus the entire friction unit may be adjusted vertically by virtue of the elongated slot 2'! through which the bolt projects.

A rotatable guide roller 28 is mounted on bolt 29 which is also carried by the upright plate 2|, the bolt projecting through a slot 30 which is vertically elongated to provide for adjustment. Knurled nut 3| serves to secure the guide roller in its vertically adjusted position.

The guide roller has spaced flanges 32 which serve to prevent disengagement of the string.

In its passage from the source to the friction elements, the string extends through a guide hole 33 formed in an upstanding lug 34 and thence upwardly and over bolt 23 and between the friction elements 22 mounted thereon. The string leaves the guide elements in a downward direction, as clearly appears in Fig. l, and passes under the guide roller 28 and thence laterally beneath the rivet I 0.

From the description shortly above of the general operation of the machine, it will be seen that removal of a board after riveting a length of string thereto, requires that the board be lifted and thence taken out of the machine laterally. In consequence of this, the run of string leaving the tensioning device T extends therefrom at various different angles during removal of a board. The roller guide 28, however, serves to maintain a uniform path of travel of the string as it passes between the gripping elements 22, and thereby to maintain uniform tension, even when the length of string beyond the roller guide is being drawn at various different angles. The flanges 32 with which the guide 28 is provided serve to prevent disengagement of the string from the guide during removal of a board.

The improvement of the present invention is also of advantage since string of different thickness may readily be employed, the tension being adjusted appropriately by a knurled nut 26. Furthermore, by employing the type of friction gripping elements 22 illustrated, knots or other irregularities in the string do not impair operation.

In addition to the foregoing, the vertical adjustability of the guide 28 facilitates use of the machine for stapling string lengths to boards of different thickness.

I claim:

1. For a machine for riveting tag strings to boards or the like, a string tensioning device comprising, in combination with a source of supply of string, a pair of cooperating spring pressed .friction gripping elements between which the string passes in its travel from said source to the riveting head, guide means for the string cooperating with the run thereof between the gripping elements and said head, and serving to maintain a uniform path of travel of the string through said gripping elements even when the run of string extending toward said head is being drawn or advanced at various different angles, and means for mounting said guide means with freedom for vertical adjustment to accommodate riveting of string to boards of different thickness.

2. For a machine for riveting tag strings to boards or the like, a string tensioning device comprising, in combination with a source of supply of string, a pair of cooperating spring pressed friction gripping elements between which the string passes in its travel from said source to the riveting head, and a guide under which the string passes in its travel from the gripping elements to the riveting head, the gripping elements and the guide being relatively adjustable in a vertical direction.

3. A string tensioning device for a machine for riveting tag strings to boards or the like, said device comprising a bracket having a base portion and an upright plate, a pair of cooperating spring pressed friction gripping elements mounted on said plate and adapted to engage a run of string passing therebetween, and a string guide also mounted on said plate under which the string passes in leaving the gripping elements, the guide being vertically adjustable so that the string may be drawn from the guide at different elevations with respect to said base portion.

4. A string tensioning device for a machine for riveting tag strings to boards or the like, including, in combination with the table of the machine on which the boards are placed for riveting pur poses, and in combination with a source of supply of string, a pair of cooperating spring pressed friction gripping elements between which the string passes in its travel from said source to the riveting head, and guide means for the string cooperating with the run thereof between the gripping elements and the head, and serving to maintain a uniform path of travel of the string through said gripping elements, even when the run of string extended toward the head is being drawn or advanced at various different angles, and the guide means further being positioned above the level of said table at such elevation that the run of string extended therefrom to the riveting head is substantially parallel to the table when the string is being riveted to a board.

5. A string tensioning device for a machine for riveting tag strings to boards or the like, including, in combination with the table of the machine on which the boards are placed for riveting pur poses, and in combination with a source of supply of string,-a pair of cooperating spring pressed friction gripping elements between which the string passes in its travel from said source to the riveting head, guide means for the string cooperating with the run thereof between the grippi'ng elements and the head, and serving to maintain a uniform path of travel of the string through said gripping elements, even when the run of string extended toward the head is being drawn or advancedat various different angles, and the guide means further being positioned above the level of said table at such elevation that the run of string extended therefrom to the riveting head is substantially parallel to the table when the string is being riveted to a board, and means providing for adjustment of said guide means toward and away from the table, to facilitate riveting of string to boards of different thickness.

HAROLD PARKINSON. 

